It is often desirable to mount a ceiling fan in a completed room. However, problems arise if wires have not been run between the location of the ceiling fan and a wall switch. Therefore, remotely controllable ceiling fans are used so that the walls need not be reconstructed to run wires.
One type of ceiling fan is a ceiling mounted fan and light assembly remotely controlled by radio signals having two channels to control the fan and light remotely to drive the motor and light at different levels setting the rotation speed of the fan and illumination of the light. Such an assembly is disclosed in U.S. Pat. No. 4,621,992 granted Nov. 11, 1986 in the name of Paul G. Angott, and assigned to the assignee of the subject invention. The patent discloses a ceiling fan which receives a dual channel signal from a remote transmitter having a fan control button and a light control button, wherein sequential depression of the buttons increments counters within the fan and light control to change the level speed of rotation and illumination, respectively. The problem with this type of assembly is that frequencies of the dual channel signal is fixed, and if control of more than one ceiling fan if desired, the electronics must be replaced.
Another type of remotely controlled ceiling fan assembly includes an infrared transmitter and a control circuit on the ceiling fan to regulate the speed of a ceiling fan, and reverse the direction of the ceiling fan, and control a light on or off. The infrared transmitter is directive so that a single receiver may be controlled without actuating additional receivers. Such an assembly is disclosed in U.S. Pat. No. 4,371,814 granted Feb. 1, 1983 in the name of Hannas and assigned to Silent Running Corporation. This patent discloses a transmitter which includes three buttons: a first for controlling the on/off and speed of the fan motor, a second for controlling the illumination of the light, and a third for controlling the forward or reverse directions of the fan. The receiver includes a decoder for receiving the pulse modulated signal from the transmitter and producing a one of three signals: a reverse signal, a light signal indicating on or off, and a motor speed signal which is incremented on consecutive receptions. A counter receives the motor speed signal to count and control three available speeds for the motor. The problem with this type of assembly is that the light can be only illuminated on or off, and that the transmitter is directive such that control of the fan assembly 10 must be exact with respect to the transmitter to ensure signals are received.
Additionally, a ceiling fan designed and manufactured by the assignee of the subject invention uses a transmitter for transmitting dual tone radio signals to a receiver which controls the fan and light assembly. The transmitter includes two buttons for light control and motor control. The motor control button controls the speed of rotation of the fan motor and controls the direction of rotation of the motor by extended actuation of the button. The receiver distinguishes the frequencies of the transmitted dual tone signal by high and low frequency detector circuits to determine whether light or fan control is requested. The motor control is accomplished by using a flip-flop and by using AND gates receiving the outputs of the flip-flop for decoding to control the fan at one of three available speeds.
The problems with this type of system is the limited control of multiple fan assemblies without replacement of electronics due to the fixed frequency transmitted between transmitter and receiver.